What's is the biggest creativity killer?

"Fear. The prevailing corporate climate is one of fear. There is a difference between fear and being afraid. It makes sense to be afraid because it can guide you to do the right thing. Maybe if you're lucky it pushes you into action because you are afraid to be mediocre. Fear, on the other hand, creates paralysis. And to be successful you have to have the courage to act." - Alex Bogusky, Chief Creative Officer, CRISPIN PORTER + BOGUSKY